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From: Roland Dreier <rdreier@cisco.com>
To: Adrian Bunk <bunk@stusta.de>
Cc: Rob Landley <rob@landley.net>,
	Arjan van de Ven <arjan@linux.intel.com>,
	linux-kernel@vger.kernel.org
Subject: Re: Status of CONFIG_FORCED_INLINING?
Date: Thu, 24 May 2007 11:32:07 -0700	[thread overview]
Message-ID: <adawsyy5azc.fsf@cisco.com> (raw)
In-Reply-To: <20070524180704.GE4470@stusta.de> (Adrian Bunk's message of "Thu, 24 May 2007 20:07:04 +0200")

 > The problem is that inline functions in headers are intended to be 
 > called from different C files.
 > 
 > gcc might not inline it in the C files where it is called more than 
 > once.
 > 
 > But it will always inline it if it's called only once.
 > 
 > One of both will be suboptimal, but from gcc's perspective it was 
 > optimal.

Yes, we could probably get huge benefits from --combine and/or
-fwhole-program to let gcc see more than one file at a time.

But I still don't see the issue with having gcc do the best it can on
each file it compiles.  If you force the inlining, then that means
that on files where not inlining was better, you've forced gcc to
generate worse code.  (I don't see how not inlining could be locally
better on a single file but globally worse, even though it generated
better code on each compiled file)

  reply	other threads:[~2007-05-24 18:32 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-05-23 19:10 Status of CONFIG_FORCED_INLINING? Rob Landley
2007-05-23 19:42 ` Arjan van de Ven
2007-05-23 21:22   ` Adrian Bunk
2007-05-23 21:28     ` Roland Dreier
2007-05-24 12:38       ` Robert P. J. Day
2007-05-24 16:55         ` Rob Landley
2007-05-24 17:10       ` Adrian Bunk
2007-05-24 17:14         ` Roland Dreier
2007-05-24 17:47           ` Rob Landley
2007-05-24 17:47             ` Arjan van de Ven
2007-05-24 18:14               ` Rob Landley
2007-05-24 17:55             ` Roland Dreier
2007-05-24 18:07               ` Adrian Bunk
2007-05-24 18:32                 ` Roland Dreier [this message]
2007-05-24 22:41                   ` Adrian Bunk
2007-05-24 17:57           ` Adrian Bunk
2007-05-23 21:31     ` Arjan van de Ven
2007-05-24 17:12       ` Adrian Bunk
2007-05-24 16:29     ` Jan Engelhardt
2007-05-24 17:14       ` Adrian Bunk
2007-05-24 17:17         ` Arjan van de Ven
2007-05-24 17:40       ` Rob Landley

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